¶1The plaintiff was injured in New Hampshire when the right rear corner of a passing automobile grazed the left front of her own and she lost control. Possibly the operator of the passing automobile was ignorant of the collision. An important question was the identification of the defendant with that operator.
¶2The defendant testified in his own defence that he was on the road but knew of no collision. The cross-examining counsel, who had no record of conviction of the defendant, drew from him testimony that a criminal case against him involving the same alleged collision had come before the Superior Court of New Hampshire. The cross-examiner *372was allowed to ask him whether he pleaded guilty to reckless driving, and the defendant answered, “No.” Although no plea of guilty to any offence, much less any specified offence, was shown, the cross-examiner, over the exception of the defendant, was allowed to ask him whether he paid a fine on that occasion and to obtain the answer that he paid his lawyer $25, and was told that “that would square the case.” The verdict was for the plaintiff.
¶3The reception of that evidence cannot be justified on the theory that the payment was an unimportant consequence of a plea of guilty that might constitute an admission of negligence. Commonwealth v. Fortier, 258 Mass. 98. Dzura v. Phillips, 275 Mass. 283. No plea of guilty was shown. Neither can it be justified on the ground that a conviction of crime may be shown to affect credibility. G. L. (Ter. Ed.) c. 233, § 21. Only a sentence after a plea of guilty or a trial constitutes a “conviction” within that statute (Attorney General v. Pelletier, 240 Mass. 264, 310; Olszewski v. Goldberg, 223 Mass. 27), and that can be shown only by the record. Commonwealth v. Walsh, 196 Mass. 369. Commonwealth v. Homer, 235 Mass. 526, 536. The payment to the lawyer was not an admission of negligence, even if the “case” which it was to “square” involved negligence. It is true that a criminal case ordinarily cannot lawfully be compromised. But it does not appear that any part of the $25 was to be used for any improper purpose, nor even that it was to pass beyond the lawyer for the payment of costs or reparation under some requirement of a court. See Ross v. Fishstine, 277 Mass. 87.
¶4Nevertheless the admission of the evidence was prejudicial to the defendant. Commonwealth v. Homer, 235 Mass. 526, 535, 536. The error in its admission was not cured by the statement in the charge that “the fact that a criminal action or prosecution arose out of the accident is not evidence of liability on the part of the defendant in this case.”
¶5Exceptions sustained.